Properties Of Hepatocellular Carcinoma Cells Research Articles

Low methyl nutrition microenvironment as a key regulator in modulating epigenetic regulation and switching energy metabolism to stimulate hepatocellular carcinoma stemness properties

The influence of changes in dietary habits, chemical treatments, variations in the activity of one-carbon enzyme gene modifications, and liver function impairment make hepatocellular carcinoma (HCC) patients prone to marginal methyl nutrient deficiency. Hepatocellular carcinoma has consistently ranked among the top five cancer incidence rates around the world, yet the issue of methyl nutrient deficiency still lacks systematic basic scientific assessment. This study aims to investigate whether the deficiency of methyl nutrients, specifically folate, choline, and betaine, induces the stem cell-like properties of hepatocellular carcinoma cells and promotes malignant progression, as well as to clarify the potential mechanisms involved. We found that human hepatocellular carcinoma cells (HepG2) cultured in a low methyl nutrient environment exhibited the following: (1) Methyl nutrient deficiency induced self-renewal cancer stem cell characteristics in hepatocellular carcinoma cells, forming tumor spheres on the seventh day, with a greater number and larger volume observed in environments with low folate and low choline. Upon isolating the tumor spheres and re-culturing, we found that the sphere cells induced by methyl nutrient deficiency (2) showed increased intracellular NADPH, accompanied by elevated lactate concentration in the microenvironment and changes in energy-related indicators of Warburg metabolism. At the same time, the expression of post-reprogramming related proteins Sirt1 and DNMT1 was altered. In summary, methyl nutrient deficiency may promote the malignant progression of hepatocellular carcinoma through both epigenetic modifications and energy conversion. National Science and Technology Council (NSTC112-2320-B-567-001). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

GDF11 inhibits the malignant progression of hepatocellular carcinoma via regulation of the mTORC1‑autophagy axis.

Hepatocellular carcinoma (HCC) is a common malignant tumor, which is associated with a poor prognosis and high mortality rate. It is well known that growth differentiation factor 11 (GDF11) acts as a tumor suppressor in various types of cancer, including HCC. The present study aimed to determine the tumor-suppressive properties of GDF11 in HCC and to assess the intrinsic mechanisms. In the present study, the human hepatoma cell line Huh-7 was transfected with the GDF11 overexpression plasmid (Oe-GDF11) for gain-of-function experiments to investigate the effects of GDF11 on the biological behaviors of HCC cells, including proliferation, colony formation, apoptosis, cell cycle arrest, migration, invasion, epithelial-mesenchymal transition (EMT) and angiogenesis. The proliferation, colony formation, apoptosis, cell cycle, migration, invasion and angiogenesis of HCC cells were assessed by CCK-8, EdU staining, colony formation, flow cytometry, wound healing, Transwell and tube formation assays, respectively. Apoptosis-, cell cycle-, EMT-related key factors were also determined by western blot assay. Furthermore, Oe-GDF11-transfected Huh-7 cells were treated with the mammalian target of rapamycin (mTOR) activator MHY1485 for rescue experiments to explore whether GDF11 could exert antitumor effects against HCC via mediating the mTOR complex 1 (mTORC1)-autophagy axis. In the present study, GDF11 was verified to be lowly expressed in HCC cells. Overexpression of GDF11 inhibited the proliferation, colony formation, migration, invasion, EMT and angiogenesis of HCC cells, and facilitated the apoptosis and cell cycle arrest of HCC cells. Additionally, it was verified that overexpression of GDF11 inactivated the mTORC1 signaling pathway to enhance autophagy in HCC cells. Treatment with the mTOR activator MHY1485 partially reversed the tumor-suppressive effects of GDF11 overexpression on HCC. In conclusion, GDF11 may exert tumor-suppressive properties in HCC cells through inactivating the mTORC1 signaling pathway to strengthen autophagy.

Psilostachyin C reduces malignant properties of hepatocellular carcinoma cells by blocking CREBBP-mediated transcription of GATAD2B.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality globally. Many herbal medicines and their bioactive compounds have shown anti-tumor properties. This study was conducted to examine the effect of psilostachyin C (PSC), a sesquiterpenoid lactone isolated from Artemisia vulgaris L., in the malignant properties of HCC cells. CCK-8, flow cytometry, wound healing, and Transwell assays revealed that 25 μM PSC treatment significantly suppressed proliferation, cell cycle progression, migration, and invasion of two HCC cell lines (Hep 3B and Huh7) while promoting cell apoptosis. Bioinformatics prediction suggests CREB binding protein (CREBBP) as a promising target of PSC. CREBBP activated transcription of GATA zinc finger domain containing 2B (GATAD2B) by binding to its promoter. CREBBP and GATAD2B were highly expressed in clinical HCC tissues and the acquired HCC cell lines, but their expression was reduced by PSC. Either upregulation of CREBBP or GATAD2B restored the malignant properties of HCC cells blocked by PSC. Collectively, this evidence demonstrates that PSC pocessess anti-tumor functions in HCC cells by blocking CREBBP-mediated transcription of GATAD2B.

BLVRA exerts its biological effects to induce malignant properties of hepatocellular carcinoma cells via Wnt/β-catenin pathway.

The function of Biliverdin Reductase A (BLVRA) in hepatocellular carcinoma (HCC) cells proliferation, invasion and migration remains unclear. Therefore, this research intends to explore the effect of BLVRA on HCC cells growth and metastasis. BLVRA expression was analyzed in public dataset and examined by using western blot. The malignant function of BLVRA in HCC cell lines and its effect on Wnt/β-catenin pathway were measured. Analysis from GEPIA website showed that BLVRA expression was significantly increased in HCC tissues, and high expression of BLVRA resulted in worse prognosis of HCC patients. Results from western blot showed that BLVRA expression was obviously increased in HCC cell lines. Moreover, HepG2 and Hep3B cells in si-BLVRA-1 or si-BLVRA-2 group displayed an obvious reduction in its proliferation, cell cycle, invasion and migration compared to those in the si-control group. Additionally, si-BLVRA-1 or si-BLVRA-2 transfection significantly reduced the protein levels of Vimentin, Snail1 and Snail2, as well as decreased Bcl-2 expression and increased Bax and cleaved-caspase 3 expression. Furthermore, si-BLVRA treatment inhibited the protein levels of c-MYC, β-catenin, and Cyclin D1. After IWP-4 (Wnt/β-catenin inhibitor) treatment, the proliferation ability of HCC cells was significantly reduced. BLVRA expression was significantly increased in HCC tissues and cell lines, and knocked down of BLVRA could suppress the proliferation, invasion and migration in HCC cell lines, as well as induce cell apoptosis. Moreover, si-BLVRA transfection blocked the activation of Wnt/β-catenin pathway.

UCHL3 inhibits ferroptosis by stabilizing β-catenin and maintains stem-like properties of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most common type of primary hepatic liver cancer. Dysregulated Wnt/β-catenin activation is closely related to the progression of cancer. Nevertheless, the mechanism that sustains the abnormal expression of β-catenin in HCC has yet to be identified. In this study, we find that UCHL3 is overexpressed in HCC tissues and correlated with β-catenin protein level. High expression of UCHL3 is associated with poor prognosis. UCHL3 knockdown markedly reduces the protein level of β-catenin in HCC cells. TOP-luciferase activity and β-catenin target genes expression are also decreased upon UCHL3 depletion. We find that the ARM domain of β-catenin is required for the interaction with UCHL3. UCHL3 increases β-catenin protein stability via removing K48-specific poly-ubiquitin chains from β-catenin protein. Furthermore, the depletion of UCHL3 induces ferroptosis and hinders the growth, invasion, and stem cell properties of HCC cells. These impacts could be restored by the overexpression of β-catenin. In addition, the UCHL3 inhibitor TCID inhibits the aggressive phenotype of HCC through the degradation of β-catenin. In general, our results indicates that UCHL3 increases the stability of β-catenin, which in turn facilitates tumorigenesis of HCC, suggesting that targeting UCHL3 may be a promising approach for the treatment of HCC.

Circ_0031242 regulates the functional properties of hepatocellular carcinoma cells through the miR-944/MAD2L1 axis.

Circular RNAs (circRNAs) possess key functions in the pathogenesis of hepatocellular carcinoma (HCC). Nonetheless, the actions of individual circRNAs in HCC remain undefined. circ_0031242, miR-944, and MAD2L1 expression were quantified by qRT-PCR. Transwell assay was utilized to examine cell invasion and migration. Glucose consumption and lactate production were measured to assess the impact on glycolysis. The relationships among circ_0031242, MAD2L1, and miR-944 were examined via luciferase reporter assay. circ_0031242 was notably augmented in HCC. Loss of function of circ_0031242 hindered cell proliferation, invasion, migration, glycolysis, and promoted apoptosis, as well as impeding HCC tumor growth. circ_0031242 directly targeted miR-944. Inhibition of miR-944 counteracted the effects of si-circ_0031242 on HCC cells. Additionally, miR-944 was proved to directly target MAD2L1 in HCC cells. Moreover, the promotion of MAD2L1 was able to rescue the inhibition of high miR-944 expression on HCC cell progression. Meanwhile, circ_0031242 involved the post-transcriptional modulation of MAD2L1 through miR-944. This study suggested that circ_0031242 regulated tumor cell progression and tumor growth through the miR-944/MAD2L1 axis in HCC.

Leukocyte cell-derived chemotaxin 2 regulates epithelial-mesenchymal transition and cancer stemness in hepatocellular carcinoma

Leukocyte cell-derived chemotaxin 2 (LECT2) acts as a tumor suppressor in hepatocellular carcinoma (HCC). However, the antineoplastic mechanism of LECT2, especially its influence on hepatic cancer stem cells (CSCs), remains largely unknown. In The Cancer Genome Atlas cohort, LECT2 mRNA expression was shown to be associated with stage, grade, recurrence, and overall survival in human HCC patients, and LECT2 expression was downregulated in hepatoma tissues compared with the adjacent nontumoral liver. Here, we show by immunofluorescence and immunoblot analyses that LECT2 was expressed at lower levels in tumors and in poorly differentiated HCC cell lines. Using functional assays, we also found LECT2 was capable of suppressing oncogenic behaviors such as cell proliferation, anchorage-independent growth, migration, invasiveness, and epithelial-mesenchymal transition in hepatoma cells. Moreover, we show exogenous LECT2 treatment inhibited CSC functions such as tumor sphere formation and drug efflux. Simultaneously, hepatic CSC marker expression was also downregulated, including expression of CD133 and CD44. This was supported by infection with adenovirus encoding LECT2 (Ad-LECT2) in HCC cells. Furthermore, in animal experiments, Ad-LECT2 gene therapy showed potent efficacy in treating HCC. We demonstrate LECT2 overexpression significantly promoted cell apoptosis and reduced neovascularization/CSC expansion in rat hepatoma tissues. Mechanistically, we showed using immunoblot and immunofluorescence analyses that LECT2 inhibited β-catenin signaling via the suppression of the hepatocyte growth factor/c-MET axis to diminish CSC properties in HCC cells. In summary, we reveal novel functions of LECT2 in the suppression of hepatic CSCs, suggesting a potential alternative strategy for HCC therapy.

KDM5B regulates the PTEN/PI3K/Akt pathway to increase sorafenib-resistance in hepatocellular carcinoma.

Lysine-specific demethylase 5B (KDM5B) exerts its tumor-promoting functions in numerous malignancies, although the possible mechanisms by which KDM5B promotes cancer aggressiveness in hepatocellular carcinoma (HCC) have been preliminarily explored, the role of this gene in regulating sorafenib-resistance in HCC has not been studied. Thus, the present study was designed to resolve this problem, and our data suggested that KDM5B was significantly upregulated in the HCC tissues collected from patients with sorafenib treatment history. Consistently, continuous low-dose sorafenib administration increased KDM5B expression levels in the sorafenib-resistant HCC cells compared to their sorafenib-sensitive counterparts. Next, by performing the functional experiments, we found that KDM5B positively regulated sorafenib-resistance and cancer stem cell (CSC) properties in HCC cells in vitro and in vivo . Furthermore, upregulation of KDM5B-degraded phosphatase and tensin homolog (PTEN), results in the activation of the downstream oncogenic PI3K/Akt pathway. Subsequently, the rescuing experiments verified that the promoting effects of KDM5B overexpression on chemoresistance and cancer stemness in HCC cells were all abrogated by PI3K (p110) knockdown and PTEN overexpression. Collectively, those data hinted that KDM5B influenced CSC properties and sorafenib-resistance in HCC cells through modulating the PTEN/PI3K/Akt pathway, and KDM5B could be used as a potential target for the treatment of HCC in clinic.

JIB-04, a Pan-Inhibitor of Histone Demethylases, Targets Histone-Lysine-Demethylase-Dependent AKT Pathway, Leading to Cell Cycle Arrest and Inhibition of Cancer Stem-Like Cell Properties in Hepatocellular Carcinoma Cells.

JIB-04, a pan-histone lysine demethylase (KDM) inhibitor, targets drug-resistant cells, along with colorectal cancer stem cells (CSCs), which are crucial for cancer recurrence and metastasis. Despite the advances in CSC biology, the effect of JIB-04 on liver CSCs (LCSCs) and the malignancy of hepatocellular carcinoma (HCC) has not been elucidated yet. Here, we showed that JIB-04 targeted KDMs, leading to the growth inhibition and cell cycle arrest of HCC, and abolished the viability of LCSCs. JIB-04 significantly attenuated CSC tumorsphere formation, growth, relapse, migration, and invasion in vitro. Among KDMs, the deficiency of KDM4B, KDM4D, and KDM6B reduced the viability of the tumorspheres, suggesting their roles in the function of LCSCs. RNA sequencing revealed that JIB-04 affected various cancer-related pathways, especially the PI3K/AKT pathway, which is crucial for HCC malignancy and the maintenance of LCSCs. Our results revealed KDM6B-dependent AKT2 expression and the downregulation of E2F-regulated genes via JIB-04-induced inhibition of the AKT2/FOXO3a/p21/RB axis. A ChIP assay demonstrated JIB-04-induced reduction in H3K27me3 at the AKT2 promoter and the enrichment of KDM6B within this promoter. Overall, our results strongly suggest that the inhibitory effect of JIB-04 on HCC malignancy and the maintenance of LCSCs is mediated via targeting the KDM6B-AKT2 pathway, indicating the therapeutic potential of JIB-04.

M6A-Mediated Upregulation of LINC00106 Promotes Stemness and Metastasis Properties of Hepatocellular Carcinoma via Sponging Let7f.

Background: Hepatocellular carcinoma (HCC) cells exhibit the stemness property, which makes the patient with HCC prone to tumor recurrence and metastasis. Despite the prominent regulatory role of long non-coding RNAs (lncRNAs) in tumor stemness, the roles and molecular mechanisms of LINC00106 in HCC are poorly understood. Methods: LINC00106, let7f and periostin expression levels in tissue specimens and cell lines were assessed through qRT-PCR and immunohistochemistry (IHC). Various in vivo and in vitro assays, namely sphere/colony formation, proportion of side population cells (SP%), invasion, migration, western blot, and murine xenograft model were employed for assessing the stemness and metastatic properties of HCC cells. Luciferase reporter assays, RNA-seq, RNA pull-down, RNA immunoprecipitation (RIP) were conducted to clarificate the target gene and analyze the underlying mechanisms. Results: LINC00106 was prominently upregulated in tissues and cell lines of HCC. Patients having a high LINC00106 level exhibited a poor outcome. Under in vivo and in vitro conditions, the stemness and metastatic properties of HCC cells were augmented by LINC00106. Additionally, LINC00106 was found to sponge let7f to upregulate periostin, which lead to the activation of periostin-associated PI3K-AKT signaling pathway. Moreover, m6A methylation was found to cause LINC00106 upregulation while maintaining LINC00106 RNA transcript stability. Conclusion: m6A methylation triggers the upregulation of LINC00106, which promotes the stemness and metastasis properties in HCC cells by sponging let7f, thereby resulting in periostin activation. The findings indicate the potential of LINC00106 as a diagnostic marker and therapeutic target for HCC.

Spindle and kinetochore-associated complex subunit 3 (SKA3) promotes stem cell-like properties of hepatocellular carcinoma cells through activating Notch signaling pathway.

BackgroundCancer stemness contributes to hepatocellular carcinoma (HCC) initiation, metastasis, drug resistance, and recurrence. The spindle and kinetochore-associated (SKA) complex has been shown to be involved in tumor progression; however, its effects on cancer stem cell-like properties have not yet been examined. This research sought to study each subunit of the SKA complex in HCC systematically.MethodsBioinformatic analyses were carried out to examine the expression and clinical data of the SKA complex’s each subunit in HCC. The expression of the target genes was detected by quantitative reverse transcription-polymerase chain reaction and Western blot assays. Clone formation and Transwell assays were performed to assess the proliferation and migration abilities of the SKA complex’s each subunit. Sphere formation assays and subcutaneous xenograft experiments were performed to investigate the effects of SKA complex subunit 3 (SKA3) on the self-renewal and tumorigenic abilities of HCC.ResultsEach subunit of the SKA complex was highly expressed in HCC, but only SKA complex subunit 1 (SKA1) and SKA3 were associated with the poor overall survival of HCC patients. Additionally, the HCC cells overexpressing SKA3 exhibited increased migration, invasion, proliferation, self-renewal, Sorafenib resistance and tumorigenic abilities. Notch signaling played a vital role in the process by which SKA3 promoted HCC stemness.ConclusionsSKA3 promotes HCC stem cell-like properties via the Notch signaling pathway. As SKA3 appears to act as a regulator of stemness in HCC, it might be a potential molecular target for HCC.

GDF11 restricts aberrant lipogenesis and changes in mitochondrial structure and function in human hepatocellular carcinoma cells.

Growth differentiation factor 11 (GDF11) has been characterized as a key regulator of differentiation in cells that retain stemness features. Recently, it has been reported that GDF11 exerts tumor-suppressive properties in hepatocellular carcinoma cells, decreasing clonogenicity, proliferation, spheroid formation, and cellular function, all associated witha decrement in stemness features, resulting in mesenchymal to epithelial transition and loss of aggressiveness. The aim of the present work was to investigate the mechanism associated with the tumor-suppressive properties displayed by GDF11 in liver cancer cells. Hepatocellular carcinoma-derived cell lines were exposed to GDF11 (50 ng/ml), RNA-seq analysis in Huh7 cell line revealed that GDF11 exerted profound transcriptomic impact, which involved regulation of cholesterol metabolic process, steroid metabolic process as well as key signaling pathways, resembling endoplasmic reticulum-related functions. Cholesterol and triglycerides determination in Huh7 and Hep3B cells treated with GDF11 exhibited a significant decrement in the content of these lipids. The mTOR signaling pathway was downregulated, and this was associated witha reduction in key proteins involved in the mevalonate pathway. In addition, real-time metabolism assessed by Seahorse technology showed abridged glycolysis as well as glycolytic capacity, closely related to an impaired oxygen consumption rate and decrement in adenosine triphosphate production. Finally, transmission electron microscopy revealed mitochondrial abnormalities, such as cristae disarrangement, consistent with metabolic changes. Results provide evidence that GDF11 impairs cancer cell metabolism targeting lipid homeostasis, glycolysis, and mitochondria function and morphology.

Naa20, the catalytic subunit of NatB complex, contributes to hepatocellular carcinoma by regulating the LKB1\u2013AMPK\u2013mTOR axis

N-α-acetyltransferase 20 (Naa20), which is a catalytic subunit of the N-terminal acetyltransferase B (NatB) complex, has recently been reported to be implicated in hepatocellular carcinoma (HCC) progression and autophagy, but the underlying mechanism remains unclear. Here, we report that based on bioinformatic analysis of Gene Expression Omnibus and The Cancer Genome Atlas data sets, Naa20 expression is much higher in HCC tumors than in normal tissues, promoting oncogenic properties in HCC cells. Mechanistically, Naa20 inhibits the activity of AMP-activated protein kinase (AMPK) to promote the mammalian target of rapamycin signaling pathway, which contributes to cell proliferation, as well as autophagy, through its N-terminal acetyltransferase (NAT) activity. We further show that liver kinase B1 (LKB1), a major regulator of AMPK activity, can be N-terminally acetylated by NatB in vitro, but also probably by NatB and/or other members of the NAT family in vivo, which may have a negative effect on AMPK activity through downregulation of LKB1 phosphorylation at S428. Indeed, p-LKB1 (S428) and p-AMPK levels are enhanced in Naa20-deficient cells, as well as in cells expressing the nonacetylated LKB1-MPE mutant; moreover, importantly, LKB1 deficiency reverses the molecular and cellular events driven by Naa20 knockdown. Taken together, our findings suggest that N-terminal acetylation of LKB1 by Naa20 may inhibit the LKB1–AMPK signaling pathway, which contributes to tumorigenesis and autophagy in HCC.

Anti-Metastatic Effect of Gold Nanoparticle-Conjugated Maclura tricuspidata Extract on Human Hepatocellular Carcinoma Cells.

PurposeWe aimed to study green-synthesized gold nanoparticles (GNPs) from Maclura tricuspidata (MT) root (MTR), stem (MTS), leaf (MTL), and fruit (MTF) extracts and evaluate their anti-metastatic properties in hepatocellular carcinoma cells. Maclura tricuspidata belongs to the Moraceae family and is widely used as a traditional medicinal plant given its biological activities.MethodsWe quantified the phenolic and flavonoid contents, reducing capacity, and antioxidant activity of all four extracts. The facile and optimum synthesis of MT-GNPs was visualized using UV-vis spectra and dynamic light scattering (DLS). Surface morphology, selected area electron diffraction (SAED), and fast Fourier transform (FFT) pattern of MT-GNPs were assessed using high-resolution transmission electron microscopy (HR-TEM). The crystallized gold pattern of MT-GNPs was evaluated using energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The functionalizing ligands of MT-extracts and MT-GNPs were determined using Fourier-transform infrared spectroscopy (FT-IR). The photocatalytic capabilities of MT-GNPs were assessed by measuring the reduction of rhodamine B and methylene blue. Cell viability assay was detected using Cell Counting Kit-8 solution. Anti-migratory and anti-invasive effects were assessed using cell migration and invasion assays. Matrix metalloproteinase (MMP)-9 and phospholipase D (PLD) enzymatic activities were measured using gelatin zymography and Amplex Red PLD assay, respectively. Western blotting and luciferase assay were used to detect protein expression.ResultsAll extracts had high phenolic and flavonoid contents and strong antioxidant and reducing capacities. Results from UV-Vis spectra, DLS, HR-TEM, EDS, XRD, and FT-IR showed the successful formation of MT-GNP with surface morphology, crystallinity, reduction capacity, capsulation, and stabilization. MTR-GNPs and MTS-GNPs had better catalytic activities than MTL-GNPs and MTF-GNPs for reduction of methylene blue and rhodamine B. Moreover, MTS-GNPs and MTR-GNPs exhibited the highest anti-migratory and anti-invasive potential and seemed to be more biologically active than the MTS and MTR extracts. Treatment with MT-GNPs decreased the enzymatic activity, translation levels of MMP-9 and PLD1. Our results showed that MTS-GNPs and MTR-GNPs could dramatically reverse transforming growth factor-β-induced vimentin and N-cadherin upregulation and E-cadherin downregulation.ConclusionThe application of GNPs as a potential treatment approach for hepatocellular carcinoma can improve therapeutic efficiency.

Catechol inhibits epidermal growth factor-induced epithelial-to-mesenchymal transition and stem cell-like properties in hepatocellular carcinoma cells

Epithelial-mesenchymal transition (EMT) is a major cellular process in which epithelial cells lose cell polarity and cell-cell adhesion and become motility and invasiveness by transforming into mesenchymal cells. Catechol is one of the natural compounds present in fruits and vegetables and has various pharmacological and physiological activities including anti-carcinogenic effects. However, the effects of catechol on EMT has not been reported. Epidermal growth factor (EGF) is one of the growth factors and is known to play a role in inducing EMT. The present study showed that catechol suppressed not only the morphological changes to the mesenchymal phenotype of epithelial HCC cells, but also the reduction of E-cadherin and the increment of Vimentin, which are typical hallmark of EMT. In addition, catechol suppressed EMT-related steps such as migration, invasion, anoikis resistance acquisition, and stem cell-like characterization through the EGFR-AKT-ERK signaling pathway during liver cancer metastasis. Therefore, these results suggest that catechol may be able to regulate the early metastasis of liver cancer in vitro.

LncRNA RUNX1-IT1 which is downregulated by hypoxia-driven histone deacetylase 3 represses proliferation and cancer stem-like properties in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is characterised by a hypoxic microenvironment and a high rate of heterogeneity and recurrence, and the presence of cancer stem cells (CSCs) in HCC may well explain both of these pathological properties. There is mounting evidence that long non-coding RNAs (lncRNAs) participate in carcinogenesis and maintain cancer stemness of HCC cells. However, the expression modes, regulatory mechanisms and potential roles of stemness-related lncRNAs in HCC are still obscure. LncRNA RUNX1-IT1 is the intronic transcript 1 of the RUNX1, which is also known as chromosome 21 open-reading frame 96 (C21orF96). Although the functions of the RUNX1 have been identified in different diseases, the function and its potential mechanisms of the lncRNA RUNX1-IT1 in HCC still remains to be largely unknown. In this study, we verified that the expression of LncRNA RUNX1-IT1 was decreased in GEO data set, HCC samples and correlated with unfavourable clinicopathologic characteristics and poor prognosis. RUNX1-IT1 repressed HCC cell proliferation, cell cycle progression, invasion and cancer stemness and induced apoptosis in vitro. Overexpression of RUNX1-IT1 impaired the growth, metastasis and stem-like features of HCC cells in vivo. Mechanistically, RUNX1-IT1 directly bound to miR-632 and acted as competing endogenous RNA to facilitate the expression of the miR-632 target gene GSK-3β and subsequently modulate the WNT/β-catenin pathway in HCC cells. Furthermore, hypoxia-driven histone deacetylase 3 (HDAC3), as an upstream regulatory mechanism, was critical for the downregulation of RUNX1-IT1 in HCC. Thus, lncRNA RUNX1-IT1, as a regulator of hypoxia, may function as a potential therapeutic target for conquering HCC.

Actinomycin D inhibits the expression of the cystine/glutamate transporter xCT via attenuation of CD133 synthesis in CD133+ HCC

Liver cancer is one of the most frequently occurring types of cancer with high mortality rate. Hepatocellular carcinoma (HCC) frequently metastasizes to lung, portal vein, and portal lymph nodes and most HCCs show strong resistance to conventional anticancer drugs. Cancer stem cells (CSCs) are considered to be responsible for resistance to therapies. Hence, recent advancements in the use of liver cancer stem cells (LCSCs) are rapidly gaining recognition as an efficient and organized means for developing antitumor agents. We aimed to use a non-target-based high-throughput screening (HTS) approach to specifically target α-fetoprotein (AFP)+/cluster of differentiation (CD)133+ HCC present in mixed populations of HCC cells and hepatocytes.Herein, we identified actinomycin D (ActD) as a potential antitumor agent that significantly inhibits activity of LCSCs without affecting the co-cultured hepatocytes. To determine the mechanism of ActD-induced tumor-specificity in LCSC, we applied various cell-based assay models in vitro. In fact, ActD significantly increased reactive oxygen species (ROS) accumulation and DNA damage in Huh7 HCC cells, but not in Fa2N-4 cells, immortalized hepatocytes. Treatment of spheroid-forming LCSCs with ActD effectively decreased spheroid formation and the CD133+ HCC cell population. Importantly, these ActD-mediated effects are a result of inhibition of cystine/glutamate transporter xCT expression, via attenuation of CD133 synthesis. These results indicate that ActD suppresses stemness and malignant properties in HCC cells through destabilization of xCT, by inhibition of CD133 expression in LCSCs. The effects of ActD on LCSCs provide novel therapeutic strategies for targeting cancer stem-like cells in liver cancer.

Cancer-associated fibroblasts endow stem-like qualities to liver cancer cells by modulating autophagy.

PurposeBoth cancer-associated fibroblasts (CAFs) and liver cancer stem cells (LCSCs) play an important part in the tumorigenesis, development and metastasis of hepatocellular carcinoma (HCC). Moreover, the stem-like properties in HCC cells could be promoted by CAFs. However, the mechanism remains largely unknown.Patients and methodsWe used conditioned medium (CM) of CAFs to culture Huh7 cells. Stemness of the cells was then examined mainly by sphere formation assay while stemness-associated genes including Nanog, Sox2 and Oct4 were measured by Western blotting. Immunofluorescence staining, Transmission Electron Microscope as well as Western blotting were performed to detect the level of autophagy in Huh7 cells.ResultsIncreased level of stemness and autophagy was observed in HCC cells cultured in CAFs-CM compared to the control group. Activation of CAFs-induced autophagic flux could be inhibited by Chloroquine (CQ), which can accumulate LC3-II protein and increase punctate distribution of LC3 localization. Treatment of HCC cells with CQ effectively reversed the CAF-induced stemness, invasion, and metastasis ability in these cells. In vivo, Huh7 cells inoculated together with CAFs developed significantly larger tumors than Huh7 cells injected alone. Moreover, blockage of autophagy in Huh7 cells by CQ greatly reduced the growth of xenografted tumors of Huh7 cells combined with CAFs.ConclusionThese results reveal that CAFs are capable of promoting stemness and metastasis of HCC cells and blocking autophagy could markedly attenuate the stemness enhanced by CAFs, suggesting that targeting autophagy in HCC could be an effective strategy in HCC treatment.

GDF11 exhibits tumor suppressive properties in hepatocellular carcinoma cells by restricting clonal expansion and invasion

Growth differentiation factor 11 (GDF11) has been characterized as a key regulator of differentiation in cells that retain stemness features, despite some controversies in age-related studies. GDF11 has been poorly investigated in cancer, particularly in those with stemness capacity, such as hepatocellular carcinoma (HCC), one of the most aggressive cancers worldwide. Here, we focused on investigating the effects of GDF11 in liver cancer cells. GDF11 treatment significantly reduced proliferation, colony and spheroid formation in HCC cell lines. Consistently, down-regulation of CDK6, cyclin D1, cyclin A, and concomitant upregulation of p27 was observed after 24 h of treatment. Interestingly, cell viability was unchanged, but cell functionality was compromised. These effects were potentially induced by the expression of E-cadherin and occludin, as well as Snail and N-cadherin repression, in a time-dependent manner. Furthermore, GDF11 treatment for 72 h induced that cells were incapable of sustaining colony and sphere capacity in the absent of GDF11, up to 5 days, indicating that the effect of GDF11 on self-renewal capacity is not transient. Finally, in vivo invasion studies revealed a significant decrease in cell migration of hepatocellular carcinoma cells treated with GDF11 associated to a decreased proliferation judged by Ki67 staining. Data show that exogenous GDF11 displays tumor suppressor properties in HCC cells.

ADAM17 promotes cell migration and invasion through the integrin β1 pathway in hepatocellular carcinoma

ADAM17 is believed to promote tumor development by facilitating both cell proliferation and migration. In this study, we investigated the involvement of ADAM17 and the activation of the integrin pathway in the regulation of the malignant properties of hepatocellular carcinoma cells and tissues. ADAM17 was positively correlated with active integrin β1, which was determined using a human tissue microarray and an N-nitrosodiethylamine-induced HCC mouse model. We found elevated ADAM17 and active integrin β1 levels in HCC tissues compared with adjacent liver tissues, and the active integrin β1 levels were associated with tumor size and TNM grade. High ADAM17 and active integrin β1 levels in tumor tissues were significantly associated with poor survival of HCC patients. RNAi-mediated ADAM17 knockdown and integrin β1 blockade significantly attenuated the migration and invasion of HCC cells, and overexpression of ADAM17 showed the reverse effects. ADAM17 interference attenuated the intrahepatic growth and metastasis of HCC cells in an orthotopic xenograft model. ADAM17-knockdown cells showed diminished levels of active integrin β1, p-FAK, p-AKT, MMP-2 and MMP-9. ADAM17 knockdown significantly attenuated the translocation of the Notch1 intracellular domain into the nucleus, whereas overexpression of the Notch1 intracellular domain rescued the translocation and enhanced the activation of integrin β1. Our data provide evidence for ADAM17 as an important determinant of malignant properties via regulation of integrin β1 activation and Notch1 signaling. Inhibition of ADAM17 may provide viable therapeutic potential for preventing HCC metastasis.